<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <title>Index</title>
</head>
<body>
欢迎用户：<%out.println((String) request.getSession().getAttribute("username"));%>
当前在线人数为：<%out.println((Integer) request.getSession().getAttribute("usernumber"));%>
<form action="${pageContext.request.contextPath}/Invalidate" method="post">
    <input type="submit" value="退出登录">
</form>
</body>
</html>